Strapping joint



Dec. 2, 1930. l w LESUE 1,783,192

STRAPPING JOINT Original Filed March l2, 1928 `2 Sheets-Sheet l www' J.W. LESLIE STRAPPING JOINT Dec. 2, 1930 Original Filed March 12. 1928 2Sheets-Sheet 2 Patented Dec. 2, 1930 UNITED STATES PATENT oFFIcE JOHN'W. LESLIE, 0F EVANSTON, ILILINOIS,A ASSIGNOR, BY MESNE ASSIGNMENTS, T0SIGNODE STEEL STRAPPING COMPANY, A CORPORATION OF DELAWARE STBAPPINGJOINT Application filed March 12, 1928, Serial No. 260,911. RenewedMarch 1G, 1929.

yof the size or character of deformation that would provide maximumresistance to separation. Either joint strength is sacrificed t0maintain the strapping strength, or vice versa. In other Words, thetensile strength of the strapping at the seal-joint after the formationthereof has been very considerably decreased in the production of astrong joint or union between the overlapping portions of the strap orelse the inherent strength of the joint or union between strap ends hasbeen very materially decreased in order that the tensile strength of thestrap at or adjacent the joint or union may be maintained.

One of the objects of my invention is to provide an improved seal-jointfor metal strapping in which maximum strength of joint is obtainedwithout sacrificing tensile strength of the band between the joined endsof the strapping.

Another object is to provide a seal-,joint that is simple, reliable,inexpensive and readilyvproduced.

Embodiments of my invention are illustrated in the accompanying drawingsWhere- 1n:

Figure 1 is a perspective view of a package in the form ofy a boxshowing the application of strapping with my seal-joint;

Figure 7 is a bottom plan view of the sealjoint;

Figure 8 is a side elevation of a further modification of the seal-jointas applied to wire-tying binding.

I attain the desired end of maximum strength of union betweenoverlapping portions of binder strap without material sacritice of strapstrength at or adjacent the union by providing a joint wherein theuniting deformation or deformations in the central region of the joint,where the tensile strains are more equally shared by the overlappingstrap portions, have greater or more intense interlocking propertiesthan do deformation or deformations near the ends of the joint where thetensile strains must be borne in greater proportion by only one of theoverlapping strap portions.

In general, the seal-joint illustrated in Figures 1 to 4 inclusivecomprises a metal sleeve A closely encircling opposite and overlappedends B and C of a steel strapping band D with relativelyintensedeformation of the sleeve and overlapped ends B and C at their midpointsas shownin Figure 4 and less intense deformation at opposite ends of themidpoint of the seal-joint as shown Figure 3. Sleeve A is constructed ofsheet metal and closely engages strap ends B and C and serves to preventlateral movement of the ends away from one another as well as assistingin the formation of an eflicient joint. The particular type ofdeformation of the sleeve and overlapped strap ends illustrated in Figlportions juxtaposed ures 2 to 4 has been fully described in myco-pending application for patent onstrapping joints, Serial No.314,216, tiled October 22,1928.

Brielly, this type of deformation consists in the provision of pairs ofindentations 10 and 11 overla ping strap ends, the indentations of,e'cli pair being in edgewise alinement and gradually decreasing indepth away from one another with their deepest to form abutting edgeportions of strap ends B and C.

My present invention relates more particularly to the arrangement of thedeformations, each of which serves as interlocking mea-ns for the strapends, in such a manner, as to provide maximum deformation and hencemaximum joint strength at the midpoint of the seal-joint as representedby the pairs 13 of indentations and in addition thereto other and lesserdeformation of the sleeve and strap ends at opposite ends of the jointbeyond the mid portion as represented by the pairs 14 and 15respectively of indentations.

A seal-joint constructed as herein described possesses maximum jointstrength because of the intense deformation or interlocking of the bandendsat its mid-point by pairs 13 of the indentations butsuch structurealone also .weakens the tensile strength of the strappingl at themid-point of the joint. This weakening of the strap at the mid-point ofthe joint is permissible due to the fact that the strap ends overlap atthis point and each sustains a part of the tension applied to the joint.The lesser deformation and interlocking of the strap ends adjacent tothe ends of the joint and on each side of the mid-portion weakens the vstrap less than the greater deformation at the mid-point so that thetensile strength of the strap at the ends of the joint, where the loadis not divided between overlap ing portions, will be greater than at themid-point where the overlapping; portions divide the load.v And theformation of more intense deformations intermediate the ends of thejoint does not weaken the joint as a whole because the tension at thispoint is distributed between both overlapping portions.

In Figure 5 I have shown a modification of the seal-joint in which thedeformation or interlocking of sleeve E and strap ends B and C isaccomplished by transversely shearing relatively large portions 20 ofthe sleeve and strap ends at their mid-point and at opposite edges andin bending downwardly so as to provide abutting edges of the strap ends.This central or mid-point deformation forms a relatively secure jointbut in itself greatly decreases the tersile strength of the strap endsat the mid-part of the joint. Additional and lesser portions 21 atthe'opposite edges and adjacent opposite the sheared portions inopposite sides respectively of the I sleeve and ends of the sleeve andoverlapped strap ends are shearcd away and bent downwardly, thusproviding lesser deformations which better distributes the tensilestrain upon the joint so as to relieve the mid-point of such strain asmight otherwise result in rupture.

In Figures 6 and 7 I have illustrated another modiiied form of theseal-joint as applied to that type of joint illustrated and described inUnited States Patent to Flora No. 1,252,680. This type of joint consistsof a split sleeve E received about the overlapped strap ends B and C andthe parts thus assembled deformed by the application of edgewisepressure at 22 and 23. This deformation in the present'joint isrelatively intense soas to provide an extremely tight joint andinterconnection between the overlapped strap ends. As in the case of thepreferred form of seal-joint and that form shown in Figure 5, however,this intense deformation results in somewhat weakening the strapstrength at the mid-point of the joint. Additional edgewise deformations24 of lesser intensity than shown at 22 and 23 are provided in the partsat opposite sides of the mid-point and adjacent to the ends of theoverlapped strap portions. The presence of these lesser and additionaldeformations results in a distribution of strain over a greater area ofthe inter-connected straps ends so as to relieve the mid-point of thejoint from such strain as might otherwise result in rupture due to theweakening of the material through stretching and the like occurring asthe result of the relatively intense deformation.

In Figure 8 I have shown another modified form of the strapping joint asapplied to wire tying. It has been the practice in the past to tightlywind the overlapped ends 28 and 29 about one another for theirinter-connection. If the ends are wound too tightly, however, so as togreatly increase the inter-locking of the ends, the wire is weakenedthrough stretching so that the joint will break when under its normalstress.

In carrying out my invention as ap lied to wire tying, I clamp the -ends30 of t e portions 28 and 29 against movement by gripj pers 31 and twistthe overlapping wires in opposite directions at points 32 and 33 at anequal distancefrom one another and from the ends 30.` I have illustrateddiagrammatically slotted pinions 34 and gears 35 driven in oppositedirections to rotate the pinions for this purpose.

As a result of twisting the overlapped wire ends in opposite directionsat 32 and 33, a relatively intense twisted and interlocked portion 38 isformed at the mid-point of the overlapped wire ends and less intenselytwisted and interlocked portions 40 are formed on each side of th`eportion 38.

The joint so formed possesses all of the admations of va vanta-ges ofthe close interlock produced by the tightly twisted portion 38 and ofrelatively great tensile strength due to the distribution of rectilinearstresses upon Wires throughout the central part of the overlapping vvireends to relieve the central portion of an otherwise concentratedapplication of stresses upon a single wire.

v What I claim is new and desire to secure by Letters Patent of theUnited States is:

1. In a joint for interconnecting overlap- `ping binder ends, aplurality of deformations therein for interlocking the binder ends, saiddeformations being of lesser intensity at the ends of the joint than atthe central portion of the joint.

2. A joint for interconnecting overlapping binder ends comprisingrelatively great crosssectional deformation at substantially themid-point of the overlapping ends and other and lesser cross-sectionaldeformations of those portions at the opposite sides of.,` the greaterdeformation.

3. lln a joint for interconnecting overlapping binder ends, a pluralityof interlocking deformations formed in the binder ends, the deformationsat the mid-portion of the joint being relatively intense and thedeformations adjacent the ends of the joint being less intense 4. Abinder joint comprisinga deformed binder end, a second deformed binderend, means for holding the ends in adjacent overlapping and interlockedpositions, the de- "T formations at the central part of the joint and atthose parts adjacent the ends being of varying magnitude whereby thedecrease in thetensile strength at that portion having deformations ofgreater magnitude is compensated for the distribution of stresses'throughout the joint by other deformations of lesser magnitude.

` 5. A joint for interconnecting overlapping binder ends comprising aplurality of deformagnitude distributed throughout the length of thejoint whereby the decrease in tensile strength at that portion having adeformation of greater magnitude is compensated for by distribution ofstresses throughout the joint made possible by the deformations oflesser magnitude.

6. A joint for interconnecting overlapping portions of metal strapscomprising a plurality-of interlocking deformations distributedthroughout the length of the overlapping portions formed in theoverlapped strap ends, the transverse cross-sectional deformation of thestrap ends being greatest at their mid-point of the joint. r

7 A joint for interconnecting overlapping portions of metal tapscomprising a plurality of interlocking deformations distributedthroughout the length ofl the overlapping portions formed in theoverlapped strap ends. the transverse cross-sectional deformation of thestra ends being greatest at their midpoint o the joint, and means formaintaining the engaging faces of the strap ends in engagement with oneanother.

8. A joint for interconnecting overlapping portions of metal strapscomprising av metal sleeve tightly encircling the overlapped portions ofthe straps, a plurality ofv interlocking deformations distributedthroughout the length of the joint, the transverse cross-sectionaldeformation of the overlapping strap ends being greatest at theirmid-point.

9. A joint for interconnecting overlapping portions of a binder strapcomprising a plurality of interlocking deformations formed in theoverlapping portions of the strap, the deformations near the ends of thejoint being individually of less magnitude than the deformations nearerthe center thereof. 4

10. A joint for interconnecting the overlapping portions of a binderstrap comprising a plurality of interlocking deformations formed alongopposite edges of the overlapping portions, the deformations -near theends of the joint being individually of less magnitude than thedeformations nearer the center thereof.

11. A joint for interconnecting overlapping portions of a binder strapcomprising a plurality of interlocking deformations formed along an edgeof the overlapping portions to interconnect the same, the area: ofdeformation per unit length of theoverlapping portions being less at theends of the ovlapping 'portions than intermediate the en 12. A joint forinterconnecting overlapping portions of a binder strap comprising aplurality of deformations along opposite edges of the overlappingportions, pairs of said deformations being in transverse alignment andthe pairs of deformations adjacent the ends of the overlapping portionsbeing of less magnitude than pairs nearer the center. l

13. Ajoint for interconnecting overlapping portions of a binder strapcomprising a larger centralinterlocking deformation, and a smallinterlocking end deformation adjacent each end of the overlappingportions.

14.A joint for interconnecting overlaplll 16. A joint forinterconnecting overlapping portions of a flat binder strap wherein aplurality of interlocking strap deformal tions are distributedlongitudinally of the 5 overlapping strap portions, the interlockingintensity of such deformations diminishing from the central region ofthe overlapping portions toward the ends of such portions whereby thetensile strength of the band rem mains relatively high in the region ofthe ends of the interlocked overlapping portions thereof.

In witness whereof, I hereunto subscribe my name this 29th day ofFebruary, 1928. -JOHN W. LESLIE.

